Fix parameter case for the getCandles APi (dydxprotocol#432)

Author: alexey-kichin

docs/pages/indexer-client/http/markets/get_candles.mdx

@@ -51,8 +51,8 @@ pub async fn get_perpetual_market_candles(
 | `market`     | path     | [Ticker]           | true     | The market ticker.                                     |
 | `resolution` | query    | [CandleResolution] | true     | The candle resolution (e.g., "1DAY", "1HOUR", "1MIN"). |
 | `limit`      | query    | [u32]              | false    | The maximum number of candles to retrieve.             |
-| `fromIso`    | query    | [DateTime]         | false    | The start timestamp in ISO format.                     |
-| `toIso`      | query    | [DateTime]         | false    | The end timestamp in ISO format.                       |
+| `fromISO`    | query    | [DateTime]         | false    | The start timestamp in ISO format.                     |
+| `toISO`      | query    | [DateTime]         | false    | The end timestamp in ISO format.                       |
 
 #### Response